HOVER/NG CRAFT & HYDROFOIL

THE INTERNATIONAL REVIEW OF AIR CUSHION VEHICLES AND HYDROFOILS

KALERGHI PUBLICATIONS e're on ops no WITH THE WORLD'S FIRST FULL Y-OPERATIONAL HOVERCRAFT SQUADRON

BHC hovercraft have now BHC hovercraft lead the world. BHC hovercraft are the only joined the forces - as regulars Incorporating systems and hovercraft that have been used on enlisted for active service, at components proven in over 20,000 military operations - both by British home and abroad, with the hours of operation all over the Defence Forces and by the U.S. Royal Corps of Transport world, the 'I 0-ton SR.N6 carries 30 Navy. They have proved themselves Hovercraft Squadron. This fully-equipped troops or over 3 in extremes of climatic conditions, tons of freight, and is able to from tropical jungles and deserts vital decision by the British mount the latest weapons systems. to the frozen arctic - from Sweden Government to purchase BHC It cruises at 56 knots and is to Sarawak, from Thailand to the SR.NG1s for the world's first unrestricted by reefs, sandbanks, far north of Canada. fully-operational hovercraft underwater defences, ice, tide BHC strength is further emphasised squadron, marks the full state or shallows, giving military by the recent Government decision establishment of hovercraft as forces a freedom and speed of to order the larger 40-ton BH.7 in front-line vehicles with a vital movement by day or night far in both the patrol boat version and role in military operations and advance of anything feasible for the logistics support version. will undoubtedly influence conventional craft. The 10-ton SR.N6 is in full defence planning throughout production with the 40-ton BW.7 to follow shortly. the world.

BRITISH HOVERCRAFT-WORLD LEADERS IN THE HOVER TRANSPORT REVOL UTION

corporation limited FEI~I~UAIIY1967 Editor : JUANITA I

HE news that a few of the latest emigrants bound for the no mergers, a surfeit of projects and lull order books. Not all T United States are from the hovercraft industry comes as the leavers went abroad. Then, as now, many stayed in this no surprise. What does surprise is the fact that such news has country to enter more general industry. only just started to attract the attention of Parliament and the The ladies and gentlemen of the Press and the Society of national Press. As is usual in cases of industrially important British Aerospace Constructors who have been concerning matters, the Press is a long way behind on the story and has themselves with the problcm of late, shoulcl note that it is one presented an incomplete picture of the true situation to the of over twenty years' standing. Only the degree has changed public. and this has now reached the stage where practically every The journalistic term "brain drain" which has been devised major industry in the country is beginning to feel the effect. for the situation is insufficient and misleading. "Talent wast- It would be nice to know what measures the self-appointed ag,e" would be better. The westward trek of manpower may be experts on the problem envisage. How anything short of a sa~dto involve three classes. One comprises the academicians, complete reorganisation of the structure and status of technical or "way-out" men who think ten or twenty years ahead. Then staffs and pruning amongst senior executives will sufice, is there are the engineers, designers and design draughtsmen- hard to see. The operation is long overdue. Most certainly the real industrial talent and know-how is invested in this category, use of semi- or complete nationalisation to impose Civil Service and they represent the most immediately serious loss. Thirdly, status upon technical staffs will not work towards the national there is the important group of men who work with their hands, interest. Men who think and venture ahead seldom enjoy work- and of whom a considerable number have gone into Europe. ing in a lettered environment. Using the bait of higher salaries and supervisory posts, it has There are, of course, some who take solace in nationalistic been possible to entice home a few disillusioned and possibly pride. For their benefit we would point out that the work of homesick migrants. But it is only a very few, and the majority some of the earlier emigrants lrom this country appears in remain. current British hovercraft and aerospace products. We refer, of Obviously the task is to find the reason for the rot and stop course, to the American General Electric T.58 gas turbine pro- it. In this direction the politically obsessed newspapers can duced over here as the "Gnome", the various constant-speed always find a scapegoat in this or that government policy - or alternator drives that can go with this and other engines, and the lack of it. In this case they are wrong. also fuel tank and hull sealants. In addition, there are all the The first murmurings of discontent arise in a man who is major electrical and electro-mechanical components on the dissatisfied with the management under which he works, the VC-10 and BAC One-Eleven airliners, as well as the complete promotion schemes or absence of them. Poor management, lack APU of the latter. To these must be added the American pro- of quality leadership, square pegs in round holes - these are pellers that are available through British licensees for future the real instigators. To this must be added the alacrity with hovercraft. which some firms will take up licence production of a foreign It is our solemn belief that (under the leadership and guid- component rather than develop their own design. ance of Mr Wedgwood Benn) Britain's youngest Government It was largely for these reasons that thousands left the British Department, the Ministry of Technology, which may well have aircraft industry during the pinnacle years 1948 to 1958. Whilst to face conflict and opposition from older-established depart- trained men, many with apprenticeships behind them, left, ments, will nevertheless succeed in banishing the stultifying others came in from milk rounds, garages, tailoring and many effects of "talent wastage" by reshaping the long-term develop- other walks of life. These were the days of full employment, ment of British industry along productively eficient lines.

IN THIS ISSUE

People and Projects 4 Hover-Air's Hoverbat 12 A Theory Concerning the From Ferry Boats to Hovercraft - Dynamics of Hovercraft Lift 8 Some Aspects of Economics and Operation 14 Letters to the Editor 10 Hovercraft in the USSR 18 The History of Hydrofoils 19

COVER PICTUHE : A hoverterminal night scene. An SR.N6 hovercraft makes a smooth transition from water to land Hovercrc~ftttriul held in u j~luyground. The boy^ of Barnstaple Secondary Modern < School, Devonshire, give a pus17 off to their hovercraft buill by them us part of the School's applied scieizce and technology activities. Barrlstaple Scl~oolis one of 60 involved rn an applied science and techizology project intended to develop the nctive ability aid initiative in pupils which many educa- riorzalists feel i~ stifled by the acudernic strait-jacket of existing curricula. Mo.

6resundsbolagen have ordered another hydrofo~lfrom Can- Societe Bertin of 28 rue la Boetie, Paris, builders of the liere Navale 1,eopoldo Rodriyuez, Mess~iia.The craft will be Aerotrain. havc developed a ~lcwhybrid vehicle for which they a PT 20s type and will catly 110 passengerb Next summer expect to find wide application in civil engineering jobs. 6;esundsbolagen wlll operate s~xoC these hydrofo~lsbetween Caterpillar tracks ale combioed w~than alr cush~onsystem Malmo and Copenhagen. In a veh~cleIntended for farm~nguse It is sad to have excel- lent sleellng character~strc.;and to be designed to prevent soil 9( 9( -h eroslon itom the all blast Mr Frank A. Dobson of Califoril~ahas patented an all cal The Invention 15 the subject of Btrhsh Patent No 1,053,394, -a small vchrcle w~tha fan [hat 11lts ~t sllghtly dbove land, published on December 30th, 1966 wate~,snow or Ice on the "giound effect" prlnc~ple HIS corn- pany, Dobson P~oducts,will sell the complete plans and opel- atlng instruct~onslo1 $25 The cost oP mater~alsis est~matedat Mr Basil Hurle-Hobbs, a former tcst pilot, has stated that $200, exclus~veof the engtne Thc mot01 can be a un~tof l'rom his company will build a special pneumatic hydrocraft for an 7 to 15 hp such as used in mtn~aturecar.; attempt on Donald Campbell's world water speed record ol The company will also supply a cotnplele srngle-seatei w~th 276.3 i~iph.Thc craft uses a system oE air lubrication to redt~ce englne for $1,500, and can Purn~shthe Can and other parts Poi friction and drag, those who build theri own veh~cle The all car has a l~ghtwocden, plaslrc-covered frame, with the fan set In the front end at about 45" and a iudder at the England for the Canadian exercise. Oppenheimer, Assistant Managing Director (Finance); and Mr Expo '67, which opens in April in Montreal, will be the Hoddington, Assistant Managing Director (Technical). world's largest international exhibition ever staged. Hoverwork FPT Industries' general business is rubber processing and the Canada's undertaking is being supported by the National nianul'acturc of a variety of rubber extrusions and mouldings. Research Development Corporation, British Hovercraft Cor- The company also specialises in the development and manu- poration -the manul'acturers - and BP Canada. facture of flexible sheet materials and their use in flexible self- * * * sealing fuel cells for aircraft, marine cral't, and wheeled and Following one and a half years of regular operation, Hover- tracked military vehicles. Among thesc specialiscd products is (ravel Ltd, the first-ever commercially successful hovercraft the rubber/nylon laminate Hycaflex, which is currently uscd ferry service, is instituting a number of important internal for the Rexible skirts cn BIlC hovercraft. company changes. It has been decided that more responsibility FPT Industries has, for some time past, undertaken sub- and authority should be given to local company executives. As stantial business for both the British Hovercraft Corpcration a result, from January lst, 1967, the following changes are and Westland Aircraft Ltd, which has the major share holding announced : (65%) in the corporation. Mr John S. Watford, formerly manager of Hovertravel's * 4 $?

Men from Transport Command disemburlcing from one of Hover~vorlcLtd's SR.N6 hovercrnjt. Six melt will be chosen from this contingent to undergo cfew trnining by Hoverwork Ltd. The course will last six weeks. Theoretical and practical training will take place in and around the Isle of Wight Mr W. EI. Frobel, 3 mechanical esiglneer livnig In Johannes- Mr Leslie Colquhoun, chief of operations of Hoverlloyd, burg, South Afr~ca,has lecently bu~lttwo hydrofoil models has been appointed managing director of the company. Ile The smaller one 1s drlven by a propeller and works on dresel joined Hoverlloyd in 1965 from Vickers Armstrongs (Engin- pi inclples; the larger has a convent~onalspark-drlven englne eers) where he was a test pilot, chief production test pilot and wrth propeller shalt, and has done 15 knots on Germrston operations manager of the Vickers hovercraft drvision. Lake At full speed the hull 1s completely out of the water MI Frobel started on the fi~stGerman experiments in 1928 at W~esbaden on underwater wlngs w~thnew hydrofo~lsde- srgned by Baron von Schertel He accon~paniedhlm to Dessau- Rosslan In 1940, and the~ethey constiucted and bn~ltmore Vice-Admiral Ralph E. Wilson, USN (Retd), has been appointed Chairman of the Maritlme Transportatron Research than a dozen hydrofoils of d~fferenttypes Board (MTRB) of the Nat~onalResearch Counc~l,succeeding Mr Frobel was one of the men not captured by the Russ~ans V~ce-Adm~ral'W~lllam M. Callaghan, USN (Retd), who retired In 1945, and he st111 possesses two models ol the hydroIoils from the Board on September 30th, 1966 Adml~alWilson is Vlce-Pres~dcntof the J J Henry Com- pany, naval archrtects and marlne cnglneers. A graduate of the US Naval Academy, class of 1924, he served as Deputy Chief Among the innovations to be introduced rn the course of of Naval Operat~onsfrom 1958 to 1960 Following h~sretr~e- cxecut~on of the current FIVC-Yea1 Plan In the USSR 1s a ment from the Navy he was appo~ntedMa~~t~me Adm~nrstratol general speed-up of coastal passenger services. Accord~ng to and Cha~rman ol the Federal Marltime Board by Presrdent Piavdu of December Ilth, 1966, the avelage speed of these 1s Elsenhowel. to bc ~ncreasedone and a half tlmes by the replacement ol half The MRTB operates as an adv~sorygroup w~thinthe NRC ol the exlstlng vessels employed on ~nter-urbanand pleasure D~v~slonof Eng~neeringto st~mulateresearch and thc appllca- crulslng servlces Express vessels, carrying 150 passengers at a tlon of new knowledge 111 the field of mar~tlmctransportat~on speed of 25 knots, wlll be the new norm, the only type named, In seeking acceptable solut~onsto problems of water trans- how eve^, belng the Raduga, which carrles 40 more passengers portatloll, the Board wolks through specla1 commlttces and than he1 predccessor, the Aikadzva, than whlch she 1s "con- panels comprrsrng rep~esentat~vesof managerncnt, labour, srde~ablyfastel" Mentioned spec~fically1s also a 200-passengel government and a~adcm~c~nst~tutlons The Board was estab- vessel for short-d~stanceservlces, wh~ch1s one and a half tlmes l~shedIn October 1965 as a more broadly based successor to faster than her predecessor and which can stand up to waves oC the Marltime Cargo Transportat~on Conference which was Fo~cc4 formed In September 1953 The Nat~onalResearch Councrl IS the operating agency of the Nat~onalAcademy of Sc~encesand the National Academy of Engrnee~rng.The two acadein~esarc prlvate organlsations devoted to the fu~theranceof science and engineerrng and therr A motor-cyclist, fifty-two-year-old Mr Ernest Heffer, of Gos- use for human welfare They also serve as official adv~sersto port, Hants, was riding along the sealront at Lee-on-Solent, the Federal Government in sclence and technology when an SR.N5 hovercraft, from the Inter-Services Trials Unit at HMS Dacdalu;\, started to cross the road. A Royal Navy sent~yhad already held up four cars to allow thc hcvercraft across, but Mr Heffer went past them and cut In front of the craft. He was summoned to appear in court Rotork Marine Ltd, Bath, Somerset, sharing a stand with I and the case, at Gosport, was the first time a hovercraft had G. Rusto~l& Son, will exhibit for the first time at the Inter- been involved in a road traffic hearing. national Boat Show at Earls Courl on January 14th, 1967, the standard version of the Sea Truck which began production in Captain Stuart Syrad of the Royal Marines, who had been July this year. beh~ndthe controls of the hovercraft, told the court that he was travelling at 10mph. Mr Heffer claimed that there were Best described as the marine equivalent to a lorry, with a no warning lights near the slipway and alleged that the Royal flat load-carrying deck area of 170 sq ft (20 ft X 9 ft less con- Navy sentry was too late in giving a halt sign. trol pedestal), it is said to be able to carry a one-ton load fol seven miles at 20 knots in less than 2 ft of water on one gallon Mr Heffer was found guilty oC drrv~ngwithout due care and of petrol. attention, and fined £10. Its except~onal load/speed characteristics are derived from the air-lubr~catedhull principle developed In this form by Mr Jeremy Fry and first int~oduced in an "Aquagl~der" sport versioli at the previous Boat Show. The formation of a I-Iover Club of Canada, with its head The hull is constructed of fibreglass, in "eggbox" fashion, office in Fredericton, New Brunswick, was announced in with built-~nfoam buoyancy, and complete with Volvo Penta January by the Honorary Secretary for 1967, Major Peter H. Aquamat~c110/100 cngine asid all controls, the Sea Truck costs Rubie. The club will give assistance to hovercraft enthusiasts £1,875. The finished hull can be purchased wlthout engine or throughout Canada with designing, construction and handling controls for £990. A special export version, complete with all of light air cushion vehicles, and through rallies and competi- controls for the Volvo engine but w~thoutthe englne, is also tions will promote ownership of small sporting ACVs. available at £1,150. A number of extra fittings such as helms- The Hover Club oI Canada will be affiliated with the Hover man's seat, windscreen, roof, navigation lights and passenger Club of Great Britain, which will give Canadian members the benches are available at extra cost. advantage of the experience of the many home builders in the United Kingdom, and the benefit of practical advice from the club's Technical Advisory Panel. Initially the Hover Club of Canada will operate on a On December 23rd, 1966, the Berlin Aerotrain test vehicle national basis, with each Province represented on the executive completed the first phase of its tests along a 4.17 mile track committee. As membership grows, regional branches will be between Limours and Gometz. During the test a SEPR formed for competition purposes. Lord Brassey has graciously powder rocket was used to confer additional power which accepted the Honorary Presidency. greatly increased speed. Two hundred km/hr were obtained The address of the Hover Club is PO Box 341, Fredericton, with the 240 hp piston engine. but once the 1.2rn rocket was @ New Brunswick, Canada. ignited speed raced to 303 km/hr. A symposlum on High Speecl Gnidetl Transport will be held On January 24th, 1967, a cons~gnmentof Atlas lamps and at the Bolough Polytech~~ic,Boiough Road, London, SEI, on fluorescent tubes was loaded on board an SR N6 hoveicraft at March Ist, 1967 Ramsgate Harbour, Kent, and crossed the Channel to Flance The problems to be rev~ewed ale Kadai location of The cargo was the first ever to be shipped by this means, /. vehicles, signall~ngand traffic contiol, commun~cahonswlth and the crossing was an exploratory one in view of the Thor~i movlng vehldes, automat~on, appl~catlon of compute~s to Electrical Industries' increasing busmess with Common Market t~aln movement countries. Powcr reqm~emenls, suspension (wheeled veh~cleslhover- vehicles), l~nea~motor, cui~entcollect~on MI S F Sm~th(Blltish Railways Boald) and Plofessor E R Laithwaite (Imperial College, London) will take the chau at the morn~ngand afternoon sesslons I espect~vely In a supplementary statement by the Cha~rmanof Vosper The speake~swrll be Professoi I3 M Bailow, FRS (Univel- Ltd at the Annual General Meetrng, the following was said :- sity College, London), Plofessor F T Baiwell (University of "In iecent months there has been cons~derablespeculat~on as Wales), Dr L L Alston (Brltish Rallways Board), Mr R B to ou~pos~t~on In the hovelcraft field, we al~eadyhave tech- Morris (Clale College, Cambiidge) and Mr E A Rogers nlclans who have started woik on hoveicraft and who w~ll (Bl ~tishRailways Boaid) fo~mthe nucleus of our hovercraft team, and negot~atlonsare Registiat~on fo~msand the detalled proglamme foi the at an advanced stage for us to assist as mall1 sub-contractois symposlum may be obta~nedby application to the Secietaly, to Cushloncraft Ltd in the design and construct~onof a hovel- Borough Polytechn~c,Borough Road, London, SEI craft passengel /CAIferi y known as the CC 6 "In the circumstances we are In touch w~ththe Nat~onal Research and Development Corpo~ationIn iegald to ou~be~ng licensed by Hovercraft Development Ltd, which we belleve to be essential at th~sstage " The "Third International Fair of Comn~unications" will be held in Cieiioa from October 12th to 22nd, 1967. The classified list of sections for the exhibition includes the following :- Sea, rlver and road colnmunications London may soon have fire-fighting hovercraft to tackle Energy for communications riverside blazes and shlp fires, and the first of these hovercraft Air communlcatlons fire floats may operate from a new fire slation at Upper relecommunications Thames Street, near Cannon Street Station, equipped with a Further details may be obta~nedfrom Comm. Dott. Carlo special slipway. Pastorino, Piazzale J. F. Kennedy, Genoa, Italy. A London Fire Brigade spokesman said that officials had been watching demonstrations on the Solent Two problems have to be worked out-whether they can be built large enough to carry the equ~pment,and whether craft of this size will be able to pass safely under the Thames br~dges,whatever @ From April Ist, 1967, the National Physical Laboratory at the tide. Teddington IS to take over the Hovercraft Technical Group at Hythe as part of moves to strengthen Government-financed i esearch Inlo hovercraft Mr Anthony Wedgwood Benn, Ministel of Technology, stated rn the Commons thal the Hythe techn~calgroup would come under a new Hoverciaft Unit being set up at NPL A section of the new unlt would be attached to the Inter-Se~vices Hovercraft Trlals Un~tof the Min~stryof Defence Untll now, the Hythe gloup has been part of Hoveic~aft Development Ltd (HDL) a subsid~aryof the Govelnment- sponsored Natlonal Research Development Co~porat~on THE HISTORY OF (NRDC) NRDC w~llcont~nue, through HDL, to control patent rrghts for hoveicraft and hovertla~n ~nvent~ons,and to considel applicat~onsfor llcences AIR CUSHION

A spokesman for NRDC, commenting on the news that the technical group of HovercraA Development Ltd is to be trans- ferred to the National Physical Laboratory, Ministry of Technology, has stated : "Two years ago, i.e, long before the merger of the hovercraft interests (last year there was a merger of the hovercraft interests of Westland Aircraft Ltd, Vickers Ltd, in British by Leslie Hayward Hovercraft Corporation L,td in which NRDC has a 10% interest) NRDC had concluded that in due time it would be better for the hovercraft research and development facilities of its subsidiary HDL Ltd to be sustained on a national basis, and we therefore requested the Ministry to take over these facilities. It was recognized by the Corporation when it made UK and Europe, 5s 6d (incl, postage) the proposal that it would require to continue to support the @ technical group until the Minister of Technology decided that Canada and USA, $1.25 (incl. postage) the time for the handover was opportune." HIS altlcle w11l be ol most Interest Lo aelodynanircrsts and down a plug-hole repiesents a natural phys~calphenomenon T others who may have a keen applecratlon of the flow From dl1 the examples given 11 appears that In what plane the alound aircralt wlngs and the assoclated alr c~rculatlon It IS c~rculatrontakes place does not matter, but that it takes place to be understood that unless otherwise stated cve~ythlngIn thrs does mattel art~cleconcerns a hovercraft In the statlonary hoveling con- Wrth all th~sIn mrnd lt 1s worth rnvestigatrng the hovercralt drtion No tlanslat~onal effects are to be considered except to seek poss~bll~tlesand pioot as to where alr c~rculat~onmay towards the end of the artlcle where accele~atrontroni rest is take place Agarn ~t must be emphasrsed that only the stat~onary spec~ficallymentroned hoverlng condltlon IS to be considered There IS ample evrdence An IIIVISCI~perlect flurd has been assumed, the usual a5curnp- ol crrculat~ontaklng place both as a part of and as an adjunct tlon In thcoret~calae~odynamrca to the lrftlng system Fu~thermore,such c~rculationappears to The concept was founded when the autho~tr~ed to dlaw glve rlse to effects which are closely pa~alleledIn aircraft aero- parallels between the l~ftmcchanrsms or alrcraft and hovercraft dynamics Of these the author's concept of an "lnduced werght" Veiy httle has been wr~ttenon the aerodynamics of hovercralt 1s closcly analogous to the "lnduced drag" of an aircraft wlng and 11 wculd appear that a conc~setheory has not yet been developed Of coulse 11 may well be that an encompassrng Vortices theory does exlst under a classrfied heddrng LC one con~~dersthe well-known alr curtaln which IS devel- Overall the approach has been blased from the start by the oped alound the per~pheryol a hovercraft ~t can be seen that author's content~onand pet theory that nothing l~ftsw~thout an exterlor vortex 1s formed by the cscaplng alr Addltlonally, some form of crrculat~on Thus in the case of an aircraft wlng the larger propoltion of the arr curtaln which 1s dliected unde~ the 11ft IS asscciated with a clrculatron of air The well-known the hove~c~aftcan lorm another vortex or a mass of smaller expression - vortrces Fig 2 shows both poss~blesystems LIC~= rpv Slnce all IS cont~nuouslybang fed Into the Internal vortex where pattern a s~m~laramount ol all must escape from ~t;the theoly r= the clrculat~on of contrnu~tydlctates thls Thus rt 19 reasonable to a\sume that p -- the dtns~ty alr enters the rnnel chamber and rotates under the actlon or V = the veloclty 11s energy Aa the enelgy of the rndlv~dualpart~cles IS d~ssrpated ires them together thcy wlll move to the pelrphery of the chamber Flowmg Moving to other thlngs one finds that a l~ltllses only when towards the centre llne, thcy wrll then pass along the only a cable drum 1s ~otated,therelore a mass ol metal IS crrculated escape path, which IS under the maln vortex close and parallel An escalator work5 in a similar mannel Hot all currents lo the terlarn su~lace desc~ibea spllal path as they ascend and rn st111 arr the smoke Thls outflowlng all w~llrnteract wlth the voltex and ploduce lrom a clgarettc demonstrates thrs So far as anlmal life is an alea of pos~trvepressure beneath the platform Dlagranl- concerned, cl~mbrnga hrll calls fo~increased heat actlon and matrcally ~t 1s seen that a system of contra-flow equivalent to hence an Incr eased blood crlculat~on that taklng place beneath a 11it1ng aerofoll IS set up Also it Belore lcavrng th~sfasclnatrng subject ~t 19 worth mentron- wculd appear that if the total c~rculat~on,the denslty of the lng that crrculat~on appears to be assoclated wrth controlled alr and the mean veloc~tyol lhe escaplng ail are known, then descent also Mechanrcal applrances such as the 11Tt and esca- the 11ft can be calculated FI~I shows the flow and c~rculatlon lato1 ale obv~ous,whrle the voltex lormcd by water flowing dlo~rnda hftrng aelofoll Circumstantial Proof Sidewall Craf i If a hovercraft develops a pronounced list, or the surface Going back to Fig 4, one can see that if the sidewalls are were abruptly to change to give the same etrect, then serious employed to suppress the side vortex, then the velocity pattern instability can develop, capsizing being the worst possible is reduced to that of the lower part of the model. Since pressure result. It is of some interest to examine the circulation theory is a function of v the sn~allerthe velocity thcn the smaller to see if it can explain the phenomena. the induced weight. From this it is evident that the analysis Considering a full cross-section through a hovercraft in a agrees with what has been found in practice: that is, that side- canted condition, it can be seen that the lowest side will contact wall craft require a smaller power for levitation. the surface and close the air escape path. Thus momentarily For a design producing no side vortex and having a length twice the amcunt of air will follow the escape path beneath of twice the beam, the ratio of curtain length divided by unit the vortex on the raised side. The consequent increased lift area is just over 1.4 : 1, and if the length is four times the from that side will combine with the loss of lift l'rom the beam then the ratio is 1 : 1. Of course, the ratio decreases still lowered side to create a powerful turning moment about the further with higher length-to-beam ratios. CG. This at least gives some validation to the theory that lifting vortices exist under a hovercraft. Going back to wing systems, one may liken the front and rear vortices existing under the platform to the bor~ndvortex a on a model wing spanning the walls of a wind tunnel. In both Induced Effects cases the vortices end on a wall and are considered to be of The external vortex system formed by the air which does not infinite length- a situation that gives nil induced drag on an go under the platform will have an action similar to that of the aircraft. Where a peripheral air curtain exists the internal vortex trailing vortices at the tips of a finite wing. If we consider just forms a collar under the platform and can be likened to the one vortex at the end of a simple lamina it will give rise to a bound and horse-shoe vortex system of a lifting wing. vertical air velocity all over the surface. The vertical velocity Although such analogies may be tenuous, the fact that they distribution is shown in Fig 3A. Adding a second vortex to the can be made is surprising. other end gives a similar pattern which can be added to that of the first, and this is shown in Fig 3B. Naturally this vertical velocity will come to rest on the Practical Considerations surface and give rise to a stagnation pressure P = 4 pv 2 Before leav~ng the subject of ~nducedeifects one or two Since its value will be additional to atmospheric pressure it remarks and observations must he made Return~ngto Fig 4, will be equivalent to an added load and may be termed ~t IS to be noted that the veloc~tyd~btr~but~on surface as drawn "induced weight". Very obviously it arises from similar circum- applles to an infinitely thin platform Pract~caldepth comb~ned stances to those which produce induced incidence and induced w~throundlng of the edges of a typ~calhovercraft will modlfy drag on a finite aircraft wing. thls considerably Veloc~typeaks at the colners would occu~ more lnboald and have somewhat reduced values It 1s of some Efficient Planforms interest to note that the fan intakes on the SR.N4 are near the apices of its plan at points where maximum induced velocity To complete the picture one has to consider that a hovering and hence stagnation pressure would occur. platform occupies three dimensions and there will be addi- tional vertical velocity components contributed by the vortices At the intakes air will not come to rest and hence stagnation attached to the other two sides. Hence a 3-D model can be pressure will not arise there. A type of regenerative effect will constructed as shown in Fig 4. In this the vertical veloclty be obtained with the air passing back into the circulatory sys- distribution due to the end vortices is seen at the bottom and tem. An ideal arrangement would be for the entire top surface that due to the edge vortices has been added on top. The upper- to be an intake. most and shaded plane describes the total veltical velocity Again in the case of practical craft the effect ol' depth also everywhere across the platform. minimises the induced weight effect. This is seen from Fig 2, All this suggests that a criterion son~ewhatanalogous to the where some generator arms are drawn together with their aspect ratio of an aircraft wing has some importance in decid- normal velocity component. Thus, what is direct downward ing the efficiency of a lifting system. To minimise induced velocity and pressure in the case of a simple lamina becomes weight one obviously needs the maximum amount of area for side pressure and reduced downward velocities in a real case. the minimum length of peripheral curtain. It is an informative It is in the realm of induced effects that the French Bevtin exercise to work out values for scme basic shapes uslng a unit system appears to be very efficient. Their unique arrangement area. It is found that a circular planform is the most efficient employs a number of tuyeres protruding from the underside for a per~pheralcurtain and here the ratio of peripheral length of a platform. Looking at a typical cross-section as shown in divided by unit area is approximately 3.54 : 1. Other shapes Fig 5, one sees that the generator arms from the exterior vor- give higher values and are consequently not so effic~ent. tices will give rise to pressures tending to support the craft. FIG. 5

Trim Change Earller the lateral ~nstabrlrtycondrtron of a hovercraft was rnvoked as circun~stantralproof of the existence of Internal crrculat~on The known tlrm change as a hovercraft accelerates isam rest w~llbe ~nvokedas further proof The fore and aft srtuatron with the craft statlonary IS shown In Frg 6A Once rt gets unde~way the outflow beneath the forward vortex rs suppressed by the natu~al allflow Thrs volume of alr, plus that flowlng Into the system from outsrde, mu\t escape from the rear ot the cratt (theory of contrnu~ty) Hence the lrft of the Co~wardvortex IS dest~oyedwhrle that ol the real onc IS ~ncreased,and as a re\ult the craft pitches nose down In practlce thrs actlon IS tr~mmedout by the horizontal .way that ae~oforlprofiles can be derrved. In thrs drrection it is stabrlrsers whrch have to produce a negatrve lrft and so act \~o~thnotrng that some skirts have an Internal catenary agarnst the pcsltrve I~ft At first srght a problem may be to get compatlb~lltyw~th the momentum curtarn theory, which by the way IS not Invalidated by the suggested crrculat~ontheory. The momentum curtaln is Summary and Note seen as part of the circulatory system. Levitation pressure exists within the boundaries of the outflowing air stream which passes If thc theory that thele 1s a c~rculat~onIS accepted, then 11s beneath the curtain ~amrficatlonsand Impact upon hovercraft desrgn could be enor- mous A concept could be built up whlch together wlth bas~c Furthermore, such an approach to the aelodynam~csof the lorn~ulaewould allow rapld appra~salof many varratlons In system may well lead to a much better understanding of vor- part~cufa~the effects ol plantolm on the eficlency of levrtat~on tices, their effect and lechniques. Thus we may learn bow to and the effects of motlon could be mole leadrly envrsaged At handle them better and use them to best advantage in both least one shape that dcserves much attentron comcs to mlnd aircraft and hover craf. Everything tendo to suggest that an Important paranleter Finally the Ideas expressed here ale entirely those of the could be the shape of the vortex chambe~ With a surtable author. He is in no way connected wlth any firm engaged on vortex theory ~t shculd be possrble to derrve chamber contours hovercraft manufacture or research, nor yet any institute, seal lo1 maxlmuln eficlency and Sor partrcular pulposes rn the same of learning or Governmen1 agency. Comment is invited.

University of Leeds

Dear Editor, Hovertrains - Inverted 'r versus Rectangular Section Track A point in favour of the "Inverted T" scction, which does not appear to have been specifically raised in previous discus- sron on the subject, involves the manoeuvring of hovercars at tcrmrnal and other Iac~lities It would seem that any hovercar wrth a body cross-sectron whlch lk devold of plojections extendrng below the level of rts v' main lrit pads is rnhelently superlo1 In thrs respect Such a hovercar, designed to operaie normally on an inverted T type oS t~ack,would, in the absence of the vertical part of the 'I' section, possess complete freedom to move laterally in a two- d~menrloklplane Thus, all that would bc requrrcd in the form of tlack at a tcrmrnal ol other facllrty would be a flat concrete avron W~ththe addrt~onor steerable and ret~actablewheels, tiking perhaps 10:/o oT the total weight, the hovercar would [hen become more manoeuvrable than a conventional roacl bus. Hovertrack - Inverted T combined with box sections On the other hand, a hovercar with a body cross-section 34 Waterside, which extends down both sides of a rectangular section track Martham, Gt Yarmouth would certainly require the provision of more complex switch- ing arrangements. In fact, some type of traversing action in January 26th, 1967 '@ which a complete section of the track is slewed sideways would Dear Editor, appear to be necessary. The need for unadaptable set-piece For the apparent reasons of popularity and profit, the odd switching arrangements is one of the Iundamental drawbacks editor and writer continually hawk around the old potboiler of conventional railways and should be avoided if possible in that we are on the verge of sailing at twice wind speed by a new system. In this respect at least, therefore, the inverted T using hydrofoils. Thus I would tend to say to such as your holds an advantage over the rectangular section. last issue correspondent, Mu T. James, not to be too readily One of the disadvantages of the inverted T is that it is a luilcd into this well-worn trap. poor beam section and thus relatively more expensive for the By dint of long practical experiments, years ago I succeeded purpose than a rectangular box section. The accompanying in getting lifted up on sailing hydrofoils, propelled only by sketch, based on the overhead concrete girders designed for the wind velocity reacting on an aerofoil. This is a very much BARTD system in San Francisco, stiggcsts how a track section more difiicult achievement than is the relative ease of lifting might be designed which combines the advantages of both the up on foils when due to the constant level mechanical thrust inverted T and rectangular sections. The problem of debris col- provided by an engine powered propeller or jet. lection could be avoided by providing a series of gaps through the base of the vertical guide. In fact the vertical guide might Therefore, whilst it certainly can be done by sailing, it only well be manufactured as a separate piece altogether. happens as a spasmodic occurrcnce. The process seems en- Yours sincerely, tirely too dependent on the inconstant fickleness of suitable C. D. ENGI.ISIH wind and water conditions. In outcome, the opinion of some members of the Hydrofoil and Multihull Society and myself is that hydrofoil sailing is not within the accepted require- ments of the vast majority of yachtsmen who usually want to sail sufficiently at any time for their pleasure and recreation. Accordingly we went on to carefully develop the first classes of shallow draft advanced sailing yacht, such as Trifoil and Triforms, to embody an especially designed new form of hydrofoil. These configurations purposely affording only modi- fied or partial lifts for improved stabilisation and superior seakindliness, besides entirely replacing the appreciable weight and high costs attendent in otherwise providing essential forms of keel. Nicholson House Based on the aeronautical work of the Americans Wilbur and Orville Wright, these present British inventions have long High Street since been fully proved by many independent people at home Maidenhead and abroad. The operative conclusion of these delighted users Berks. infers a bird in the hand is better than a dream in the bush. Intended as a big advance on run-of-the-mill orthodox tri- marans, the concepts of the Trifoil and Triforms alternately supported by one of their asymmetric working "Hydrowings", Dear Editor, attached through streamlined " Storkcons" and low resistance The letter from Mr Gresham Cooke in your October issue "Meroloa" arms, are the synthesis of the progressive sailing has raised some interesting points concerning the development yacht. A faster yet cheaper yacht, developed to obtain a of hydrofoils in British waters. However, the possibility of wholly practical wind propelled hydrofoil system. Still to be developing new hydrofoil designs in the United Kingdom must fully appreciated, but in a variety of ways a distinct improve- have been under consideration repeatedly over many years in ment on the basically unchanged yacht of tradition, yet enough our own shipbuilding industry. like it to be capable of immediate use from the faintest breeze Our own experience in this field is limited to the economics up to a gale. of transport and studies recently undertaken for private spon- The technology was explained in the paper entitled Practicul sors in this country to establish the probable commercial Hydrofoil Sailing versus Flights of Fancy, by the H & MS in prospects for hydrofoils and hovercraft in competition with the March 1965 issue of Hovering Craft & Hydrofoil, Vol 4, established conventional ships. Using current designs of hydro- No 6. foils, some of which are in operation in niany countries in Rather than the sensationalism of extravagent prophecies of Europe and also outside Europe, it is becoming clear that a sailing at double wind speed, one must regard such realities as: strong economic basis does ex~stfor hydrofoil services, when (a) The wind, even when adequately present, seldom stays traflic justifies it and when the time advantage can be made constant enough in velocity. (b) On open water when hydrofoil to work favourably as a sales factor in those waters where sailing winds blow, the water surface gets too rough to harbours of the right type are available and where sea con- initially get something approaching a comfortable passenger ditions are not too extreme. hull accommodation up on to foils. (c) The hydromechanical The hovercraft, however, while holding out probably greater couple of reaching has the fastest sailing potential, yet the expectation for long-term economic advantage, especially in resultant heel does not assist a full hydrofoil lift configuration. the larger sizes which will soon be available, is not an imme- (d) Unlike the reserve power and (c) multidirectional ability diate commercial prospect and in many categories is not avail- of a motorboat, we found even a bit of seaweed would spoil able immediately to offer direct competition. sailing foil lift, as would much in the way of a change of As we see it, the hydrofoil and hovercraft potential will lie course, (f) hardly to rncntion close tacking requirements. in different areas and in most cases, when it is quite clear what This and more, direct information was presented many years the operational objective is, research into the requirement will ago to the editor of a specialist magazine, but he could hardly indicate the optimum vehicle to meet economic objectives. Unfortunately, far too little research of this kind, combining be expected to disseminate such findings when his publications engineering, economic and operational factors, has been done invariably indicate their next issue may tell the reader just in this country Fuller studies in this field are now surely re- how to sail at 24 knots in a 12 knot wind? quired, if our ship builders and aircraft manufacturers are to Regrettably, additional to such natural obstacles as herein concentrate on the best types for wide conlmercial sale. mentioned, it should also be considered, compared to the Yours sincerely, trifling resistance of a blade on hard ice, or even friction from ALANH. STAFFORD (Continued on page 13) A single- cat Hoverbat WUJ ~oi~~trt~ctcd011 Hover-Atr Ltd'~~tarzd ot the Internuttcrnal Boat Show at Earl's Court, London, which endcd on Januor y 14t11, 1967

by our Special Correspondent

HOSE who lead busy lrves centled on full-srze hovercraft ol doors unless mole generous accommodat~onIS available T may well be excuscd lot pursulng other hobbies In the~r spare tlme Actrve people whose llves revolve aiound drficrent Costs spheres may well take an Interest In the new mode ol trans- As purchased from Hovel-Alr Ltd, the basrc k~tof parts portatron for fun, and th~scould be a good thrng fci the costs &65 and fo~th~s one gets all the necessary trmber, ready- rndust~y The Hovel-Arr Ltd Hoverbat whrch has been pro- cut keel members, lolmers, ribs, spars, seat and control column moted nat~onallyby the Daily Exprc~shas been desrgned For A ready-assembled k~tinclud~ng Perspex canopy costs £125 and the advent~~roushandyman It can be purchased con~pleteor of course the englnes, propelleis, fan, Puel tank and Instruments in klt form have to be added The fully comprehens~vek~t containrng every Purchasing the krt of ready-formed paits and bulldlng the Item rnclud~ngthe englnes sells for around £550 craft w~llenhance the ~nte~estand edt~cationto be derrved lrom Of course, the engrnes - of whlch there are three - are such a project So fa1 as srze IS concerned, the basrc hull struc- expensive new Items and the constructor can do a lot better ture could be assembled In any small garage that wlll accom- for him5elf by addpt~ngused un~tsIngenu~ty and ~nillat~vew~ll modate a nirnl car, a bedroom or din~ngalcove The forty be requ~redbut th~sadds st111 further Interest to the exerclse manhours ~equrredcould be accounted Pol In a week or two It IS possible to employ a wide range of motor-cycle or even so that the preva~lingdomestic sltuatlon need not be dis~upted car englnes, none of which ra expensive In the used cond~t~on tor long Attachment of the englnes, hft fan, skrit and pro- In th~sway it seems possrble that a Hovetbat could be bu~lt pellers w~llrequire lurther trme and is perhaps better done out and tested for ~nsrdef 125 Assembly The construct~onaltask IS very s~mpleso far as the hull is concerned It is held together In the maln with Cascamite glue, which has excellent weathering propertres and IS urllversally employed by small boat burldcrs Most members are ol ply- wood 9n1m th~ck,whrle a few arc of 6 mm mater~al The assembly is self-jiggrng, being burlt around the base-board and two large internal keel members An average handyman's range of tocls IS all that 17 lequrred, although it appears that scveial pairs of "G" cramps are needed durlng the rnrtral gluing phase All the metal fittrngs are s~mpleand not beyond the scope ol a local garage mechan~cand hrs welding equipment Thelr quality or lack of ~t rs not gong to make a scrap of drfference to the performarice so long as they src stlong enough and not too heavy At the Dally Express Boat Show rt was possrble to inspect the prctotype mach~ne,11, details, typ~calpower plant installa- trons and plopelleis On the oppos~testde oC the stand the work of bullding up a k~tp~ogressed, and 11 was hoped to hovel 11 out at the end of the show - probably st~aighton to a customer's transpoi t Even before the Boat Show numerous rnquines had been Michcrel Childs is seen painting thc Hoverbut wlzilst Colin recelved I'rom souicei at home and abioad and st111 mole were Neule atlends to the fitting iecelved dnrlng the show Curlent k~tproduct~on is at the late of forty pel week It appcals that there IS a bottleneck In the dist~ibutlonand In dealing wlth all the inquliles at thls time All qurte undcrstandablc when one ccnsrders the small slze of last speed And rt can be made to go faster yet Dan lieece, the the orgdnlsation dcs~gner,is looking forward to testrllg one powered by the well-known Volkswagen car engine Expc~renccdhoverpilotJ say Lhai the~eis nothlng like it for thr~lls,and the trarning value of developed veislons is thought Tech~licalDetails to be consrderable Oveiland ~t was found to be Easter than onc It 1s of some rntelest to view the technrcal cha~acterrstics ol the rnllltary SR N5 vehrcles It is also hoped that develop- and mer~tsol the c~aft,they are qu~tesurprisrng In the cu~rent ment will glve even better hoveling per for mance, and already developed form whrch employs three Velocette two-cyl~nder a two-place versro~iwlth slde-by-s~deseatlng 1s bang burlt In horizontally opposed englnes, fuel In the tank and ready to go, small numbers 11 turns the scales at A ncmrnal 4001b (181 kg) The single At th~stlme Hover-AI~Ltd is engaged In the construction occupant must be added to this, so that the mlninium all-up oT a hve-place cralt fol Ccmmander Costeau and ~t 1s Intended @ weight a in the legion of 560 Ib (251 kg) Total output from Tor use in a film A large ploportion of the basic hull structure the three englnes IS 45 bhp, wh~chmeans that the powel ratio whlch ~ncorpoiatcsthe cabln has been cornplcted Three Volks- realrsed 1s in the reglon ol 180 hp per ton By comparrson, the wagen englnes wrll be fitted and the propuls~on arrangement experimental HD 1 attarned the lowest known value of 19 hp/ will be somewhat srmrlar lo that seen on the Hoverbat An tcn and the SIi N5 reyurres about 33 hp/ton early date In 1967 will see ~tscompletion Furthe1 examples However, the srtuatlon is not qu~teas poor as would seem 01 th~sbasic desrgn are loreseen for use at coast resorts to glve at first s~ght Flrst, thc Hoverbat can llft he weight of foul thc publlc joy-i~desalong the sands and Coreshore peisons, so that at maxrmum load the powel requ~rementIS about halved. Second, the design IS very fast and even the plototype has attained 50 knots (928 km/hr), so that further development can be expected to Improve the picture still (Corztznued from [rage 11) further the ballbearlngs of a pneumatic wheel on hard smooth con. Obviously a lot can be done on the power plant srde, and cietc or sand Therc remains a lather d~fferentdrag pioposl- rt 1s In thrs spheie that the amateur constiuctor can make some tron fo~even small hydrofo~lslunning In dense water experiments The Velocette is ungeared and produces rts maxi- All th~sis quite aslde fiom the problem of initially getting mum power at app~ow~matcly6,000 rpm As a result of thrs enough speed to surmount the lrft bairier hump As a practrcal h~ghrotational speed the airscrew d~ametershave to be kept of sailing seamanship, I should finally veiy low Laiger drameter airscrews would work at a higher and academrc teachei efliciency but some form of gearlng would have to be intro- mcntlon terra firma test~ngsituat~ons may be a safer sug- duced ~f cornpressrbrl~tydrag at the blade trps 1s to be avoided. gestlon thdn the Intolerance of the sea to the ~mpractical The adopt~onof a srngle englne and reduclng drives to the Needless to say, the opportunity lemalns w~deopen Foi propellers would appear ao~thconsideration some free public~ty seekei to perform on saillng hydrofoils bcfoie TV camelas These wlll need to pat~ently wait for The poslt~onrng of the two propulsrve englnes with them suitable freak cond~trons In actuality it is much mole llkely fibreglass piopellers on outr~gge~aims allows dlfferentral thrust he will stoop to resoiting to the a~tlficial~tyof being lntially to be employed lor turnlng when stdtlc or travelling slcwly towed up like a gl~der,which is all a vely drfferent arrange- Twin iudders of generous area are effective when under way ment Out of camela view, cloubtless th~sdaring exploit wlll The thlrd engine IS mounted in a fibleglass funnel-hke Intake amrdships and dr~vesa multi-blade fan which suppl~esarr for be surrounded by lescue launches, as with the abnormally developed C-Class Catamaran out-and-out lacing machlnes [he cush~on He will be instantly acclaimed the patron salnt of all yachts- men, yet trme is likely to show the vast majority of yachtsmen will not have benefited in the slightest degree In any case, Performance most sarlrng men are not the least interested In even using Hoverhcight is quoted at 10 in (254 mm), but it is in fact established advanced improvement in piactical folm, nevel slightly greater than this at maxiinum value. But it must be mrnd about buylng impractical freaks. made clear that this figure does not represent daylight clearance YOUIStluly, but rather the depth of the skirt plus clearance As already ERICKJ MANNERS,MIN, AMBIM mentioned, one result of the high power loading is the very Multihull Designei An analysis of operational factors, crew requirements and future prospects by R. L. Trillo, CEng, AMlMechE, AFRAeS Chief Development Engineer, Hovermarine Ltd.

This article is based on a paper presented to the Institution of Mechanical Engineers, Rugby Sub Branch, and the Coventry AD Graduates' and Students' Sction at Coventry on December 13th, 1966

FERRY operator contemplating the introduction of hover- A craft crn his services is confronted with a radical change in marine transport. This change from the ship demands the most careful study of the factors involved. A preliminary exam- --EFF~CT OF SPEED AND JOURNEY TIME ON PASSENGER1 C~R ~~HHY ~E-'~m~eAsEo OAT4 IN THE MOTOR I4lP. o~c,,, 1 ination of the merits of hovercraft as opposed to conventional I I- I -I ferry boats need not be complicated, however, but must at least be on a rational basis. This article is intended to summarise a few of the main factors which have a bearing on the suitability of hovercraft in ferry operation. As the hovercraft industry grows, many types of craft will become available and specific designs will appear for specific applications. As ferries, these craft will all possess a commcn property, the ability to carry n payload at a certain cruise speed. The product of this payload and speed, which may be called the potential work capacity, is the essence of the purpose of the craft and is, therefore, a logical basis upon which to examine other aspects of the craft, such as power and capital cost.

Comparative Payload 10 $5 20 A modern ferry, having a service speed of 20 knots and SPEED - KNOTS weighing 3,000 tons, may be designed to carry 210 tons of that Figure I weight in payload, ie 7%. In comparison, a hovercraft ferry of the SR.N4 type, weighing 160 tons, can carry up to 374% of crossings of up to twelve hours, ET reaches a value of 3.5 and its weight in payload, ie 60 tons. Consequently, it is seen in this speeds rise as high as 22 knots. For the longer journey more example that 60 tons carried at 70 knots is equal in work capa- accommodation volume per passenger is provided and so rela- city to 210 tons carried at 20 knots = 4.200 ton knots. As will t~velyfewer passengers can be carried and sea states are higher be shown later, the actual work achieved in a day's opelation so that the power-to-payload ratio increases. Overnight boats will depend upon turnround time, block speed and utilisation. show even higher ET values, reflecting the drop in payload The overall efficiency in terms of transport capability may be carricd as a result of providing overnight accomn~odation.The judged by the amount of installed power lequired per unit of ET level of the SR.N4 hovercraft is seen to bc well placed, work capacity. Fig 1 shows this parameter for a number of especially bearing in mind the speed of 70 knots. At 3.5 it is a European ferry boats (as listed in The Motor Ship, December little higher than the short-duration boats but since the craft is 1965), and for the SR.N4 It can he seen that for ferry boats some three to four times faster than ~iconventional ferry boat operating on crossings of less than one hour duration, the this means that some overnight trips can become day trips. horse-power per ton knot values (ET) are mostly between one and two and the highest service speed is 17 knots. For longer * Formerly of Hovercraft Development Ltd. Ah hovercraft size decreases, hump drag does become a greater percentage of the total, and in the early days of hovercraft development some of the smaller craft experienced difficulty in "getting over the hump", aggravated by reduced thrust and increased aerodynamic drag in a head-wind condition.

Underwater Fouling A power increment which has to be considered in the pro- visicn of adequate installed power for ferry boats is that due to marine growth fouling. One aspect of marine growth fouling which is pertinent to hovercraft is that of slipway fouling, which could presumably make some small contribution towards minimising skirt wear over the slip at low tide. Marine fouling cn a boat may cause, over a twelve-month period, up to a 30% increase in power to propcl it at the same speed as in its clean condition. There is no corresponding problem with hovercraft. On the other hand, hovercraft are more sensitive to waves and wind than ferry boats and consequently sufficient installed power must be provided to give the desired cruise speed undcr the majority of weather conditions during operation.

Figure 2 Capital Cost The capital cost or first cost of a craft has a significant effect on the overall operating costs of a transport system. In judg- Observing from Fig 1 that the installed power requirements ment oC whethcr a craft is expensive or cheap, it is all too related to work capacity are not dissimilar for ferry boats and often clear that the basis of reckoning is at fault. One hears hovercraft, it is interesting to examine how the power require- that hovercraft are more expensive than hydrofoil craft or that ments arise for the two types of craft Fig 2 shows the break- aircraft are more expensive than ships - such statements sel- down of power for a hypothetical 4,000 ton displacement ferry dom being accompanied by any basis lor the comparison. boat and a hypothetical 200 ton displacement hovercraft of When hovercraft first appeared on the transport scene it was comparable work capacity. The boat is supported by buoyancy, common practice to say that, on a pound for pcund basis, they travels through the water and incurs rapidly rising skin friction would rest somewhere between ships and aircraft. The transport drag with increase in speed. Also rising rapidly and becoming a operator is not interested in a pound for pound figure (unless greater percentage of the resistance is the induced wave drag possibly he is selling for scrap); he is much more likely to be which maniEests itself as the familiar wash. The hovercralt concerned with the capital investment in relation to the trans- prcduces no such wash, but, as Fig 2 shows, a large percentage porl productivity of the craft. In practice, the productivity will of the total power is used to support the craft on its air depend not only upon speed and payload but also craft life, cushion. A hump drag condition is reached at a relatively low block speeds, practical scheduling and load factors. Despite speed, around 15 knots in the example shown, at which the these Factcrs, a useful way of putting first costs in perspective maximum water disturbance is reached, becoming negligible is to relate them to the potential work capacity. When this is at cruising speed. The momentum drag power arises from the O done, as in Fig 3, it is found that ferry boats and aircraft are change of momentum given to the cushion air as it is acceler- on similar levels at somewhere between E200 and £400 per ton ated to craft speed en ro~iteto the cushion. Some reduction in knol. At the present time, hovercraft tend to be a little above the level of power required for hovercraft cushion systems may these figures, though the SR.N4 is in keeping with a number be expected as development proceeds. Also, improvement in or current ferry boats, which is a considerahlc achievement fan and ducting efficiency will come and the ability of skirts to when the very shcrt period of developme~it is considered in follow closely the sea's surface. With such improvements the comparison with that of the ferry boat, With ever-increasing aerodynamic drag component will tend to become a larger per- competition on sea ferry operations, we can expect to see con- centage of the total so that more attention can be expected to ventional ferry boats becoming more complex in design to be paid to hull form. Ferry boats, although experiencing only secure higher rates of working, leading to a higher escalation a few per cent of their cruise resistance as aerodynamic drag, of costs than would normally be expected. In contrast, we are occasionally severely embarrassed by aerodynamic forces would expect the hovercraft first costs to be a little eased as in gale conditions, tending to have rather high superstructure production in numbers increases. in comparison with other ships.

Effect of Shallow Water Cpi~&&$l. OF PASSENER / CAR FERRY BOAIS AND-HQWB&FI Shallow-water effects on power required differ considerably /DAY SERVICE CRAFT1 I OSBOHNF ChSTLE 1962 BUlLl UK for ferry boats and hovercraft. Some very thorough measure- 2 FALA1SE . UK ments on a Belgian Marine ferry boat provide sufficient data 3 NORWAVE $955 1 GERMANY 5 LORD WARDEN I UK with which to predict the probable power rise incurred by 6 RO 84UOOUlN 1965 ,, BELGUlM shallow water of five Fathoms, as shown in the example oC 7 YiKiNG 1 196' - NORWAY Fig 2. The increased power needed arises from changes in the 1965 . FRANC€ induced wave pattern, an increase of local velocities beneath the ship and a reduction in propulsive efficiency. It is apparent FIRST COST that the effect of shallow water on the power required is large fMILL,( and where such conditions are encountered in practice the boats concerned arc either provided with suficient margin of installed power to maintain normal spccd, or are routed around the shallow water areas. In contrast, the hovercraft suffers no such penalty at its cruising conditions-in fact, for water @ depths less than craft length a very slight reduction in induced wave drag is predicted at cruising speed. POTENllLi WORK CAPACITY - TON KNOIS JPAYLOAO I SERVICE SPEED I There is, however, an accentuation ol the low-speed hump drag in shallow water conditions, although in the example shown this does not present a serious threat to performance. COMP~RISON OF Ac~un~LOAD CARRIED BY A FERRY .80~7...... AND- .. A HOVERCRAFT.-. - . HAVING TI~E SAME- CAP~TIZL-. COSY ASSUMPTIONS FERRY BOAT HOVERCRAFI

FlRST COST ( 1.75 MILLION f 1.75 MILLION PAW080 (OESlONI 250 TONS 75 TONS

hPPROY OlSilliCEMENl LO00 IONS 200 TONS s

500 Ill/

POTENTIAL WORK CAPACITY -TON KNOTS I PhIiOh0 x SERVICE SPECOI TURN ROUND TIME-MINS XASSUMEOCONSTANTFORCONVENIENCE OFPRESENTATION I II Figure 4 Figure 5

Turnround Time Euviroumental Capability Fundamentally, a transport cralt is ol no value while Wind and waves remain as two of the most important fac- stationary - it has no earning capacity while stationary. In tors affecting the installed power requirements and, indeed, practice there are times when services have to stop for lack many other aspects of ferry boats and hovercraft. It might of people wishing to travel. During peak traffic periods, how- seem at first that the ferry boat has a distinct advantage over ever, it is obviously desirable to reduce turnround time to the the hovercraft when operating in ar. environment of wind and minimum. The particular operations required during turnround waves. On closer examination, though, it is found that the are considered during the design of the craft and in this respect hovercraft is not at all unfavourably placed in comparison. the hovercraft basic shape, an almost rectangular planform, is It is convenient to assess wind and wave situation in terms cE considerable assistance. For car ferries a straight lane, drive- of cumulative frequency of occurrence plots such as are shown onidrive-off system is possible. Many ferry boats are now in Fig 6. Such plots may be drawn, of course, for yearly, designed in this way since the additional revenue' earned, monthly or seasonal distributions. In our work on hover ferries resulting from the quick turnround, more than offsets the slight at Hovercraft Development Ltd we have thought it sensible to increase in capital cost. Scandinavian ferry operators are select two frequency-of-occurrence levels for design purposes. achieving loading and unloading rates on a level with those We consider that for 857L of the year a hover ferry should be expected for large hovercraft such as the SR.N4. Fig 4 shows capable of operating without any restrictions. This would mean the effect of turnround on the total load carried by a hover- in relation to the sample wind and wave conditions shown in craft and a ferry boat in twelve hours of operation. The two Fig 6 that on a cross-Channel route in the area shown, a craft I~ypotheticalcraft have the same potential work capacity, 5,250 would be designed to operate efficiently and comfortably in ton knots, and the same capital cost, £1,750,000. It is seen that waves up to 6 ft in height and in mean winds up to 20 knots, for the same load transported, the hovercraft offers over three together with an allowance for short-duration gusts of up to times the frequency of service. Even if a substantial reduction perhaps 35 knots. For more severe conditions, up to 98% or in turnround time is achieved for the ferry boat, at the very 99?< or the time the craft would be capable of operating, but, best it would probably only offer an additional two services in if necessary, a reduced speed and/or a reduction in payload a twelve-hour day. Alternatively, it could mean the same num- would be accepted. These conditions would imply operations ber of services but at reduced service speed, requiring less continuing in wave heights of up to 10 ft and steady winds up installed power. At the present time, loading and unloading to 30 knots. Experience with the 9 ton SR.N6 on the Solent rates on UK services are below Scandinavian levels and current would suggest that the above figures are very conservative. hovercraft thinking. Consequently, by introducing hovercraft Despite this evidence, the hovercraft is more sensitive to wind on these routes, having the same potential work capacity as the and waves in terms of speed than is the comparable ferry boat. ferry boats, we might expect, during peak traffic periods, a 30% increase in productivity resulting directly from savings in turnround time.

Crew Requiremerits I FREQUENCIES OF OCCUR~NCEOF ANNUAI W~NOS AND WAVES A revlew of current passengericar ferry boats showed that a boat having the work capacity of the SR.N4 hovercraft would have at least eight times the number of crew members, ie forty- eight as against SIX.Fig 5 shows the effect of journey time on crew numbers required, from which the penalty of providing overnight accommodation is obvious With manpower costs always tending to increase, the poss~bilityas shown by the SR.N4 of a large reduction in this component of operating costs is a very attractive feature. Catering crews are carried on many ferry boats but are not yet contemplated for hovelcraft, the one-third to one-quarter journey time being a decisive fac- tor here. It is interesting to see, though, that on two Baltic ferry boats, the Visby and Gotland, pre-packaged meals are being served, avoiding the use of highly qualified kitchen staff and achieving a considerable and important saving in space. Developments such as this and the use of aircraft-type seating 0 5 10 20 30 50 70 80 85 90 95 88 99 9999 PERCENTAGE OF YEAR THAT WINO OH WAVES ARE LESS THAN TliE VALUE SHOWN on ferry boats seem to point to passenger facilities approaching - those in air transport as competition with hovercraft begins. Figure 6 At a wave herght of 6 ft and a wrnd of 17 knots (approx~mately Noise Effects the 8576 condltloni for the Enghsh Channel area), the worst A hovelcraft uces power lo1 p~opuls~onand support; the penalty produced by a head sea on a ferry boat 1s only a 4% nolse ol aniph~b~oushovercraft, as generally referred to, has loss In speed from the calm-water, st~ll-a11cond~t~on Although been the external nolse arlslng from the tho maln machinery 4% may only ~epiesentabout a 1 knot d~opIn selvlce speed, components used lor propuls~on the alr p~opeller and the to regaln th~sspeed would requlre about a 147h lncredse In engrne 01 these two sources, the arr plcpeller has been found power, hence the need Cor A good Installed power margln to be dominant Tb~ssrtuat~on has been due solely to the A hovercraft. by vlrtue of ~tsgreater speed and g~eaterpei- economic necesslty of using exlrtlng ancraft-type propellers centage payload carrylng ablllty, 1.; about one-thrrd of the Such propellers are des~gnedto provide a good performance length of a lerty boat havlng the same work capac~tyConse- under ancraft Alght cond~t~cns,whlch means, In most Instances, quently, on thls basrs the waves are physically of much greater a rotat~onalt~p speed of between 800 and 900ft/sec When s~gn~ficanceto the hovercraft used on hovercraft these p~opellersmust st111 be operated at Contl olllng the hovercraft speed / wave he~ghtrelatronsh~p th~sspeed rn order to secure an efic~entthrust level fol the as much as resistance, 15 a cons~derat~onof an acceptable powel Input All ev~denceol propeller nolse polnts to relatrvely accele~at~onboundary, and ol how the crart w~lll~de over the h~ghnoise levels berng lnevrtable at such t~pspeeds even at lnfin~telyvarylng sea su~race From cxperlence gamed to date drstances From the propeller whlch may be cons~deredexces- w~thhovercraft, the frequency of motlon IS h~gherthan that slve, for Instance 500 to 1,000 tt W~thoutthese readlly avail- encounte~edIn normal passenger-carlylng shlps such as terry able propellers, however, hovelcraft progless would have been boats F~omthe passengel comfort polnt of vlew, thls rs a good clowed cons~derably,awaltlng the development of an Improved result, movlng away from rnot~onsliable to cause seasickness des~gnrequlrlng cons~derabledevelopment effort Development The des~gnalm, of course, 1s to reduce to the mlnlmurn the work IS now In hand w~ththe propeller manufacturels whlch accelerat~onfelt by the passengers The frequency of accelera- wlll lead to the provrslon of low-t~p-speed,large-blade-area tlon IS 1s vely much dependent upon the length of the hover- propellers whlch should be very quret In relat~onto plesent c~aftand the waves over wh~ch~t IS tlavell~ng levels Although ~t 1s true that only a handful of passengers out ol Non-amph~b~ouss~dewall hovercraft can be dr~ven,of course, something l~ke500,000 who have travelled on hoverc~afthave by convent~onalmarrne screws, and In th15 respect are as srlent been sea~~ck,~t would be a most worth-wh~leaccomplishment as shrps Development of th~stype of hoverclaft has now been IF th~sunpleasant bu~lncsscould be avoided completely The taken up rn the UK by Hovelmar~neLtd of Southampton hovercraft may well p~ov~dethe opportun~tyto ach~evethis Brrtten-Nolman Ltd bas sough1 another sclutlon to the alr- result For overwater travel p~opellernolse problem by drlvlng the CC-4 and CC-5 hover- craft w~thcentrifugal lan efflux, and the result has shown art app~eclablereduct~on in nolse, though at some unavoidable Re]>rirzted frorn "The Motor Ship", November 1966 loss In propulsive eficrency

L. RODR QUEZ-- SUPRAMAR I PATENT Messina, Italy Hovercraf

USSR

Commander Edgar Young, WN(Retd)

NTERESTING revelations about the development of hovercral't I in the USSR were made in Pravda of December 7th, 1966, by their Special Correspondent, I<. Raspyevin, as the result of Mr Valentine Ivanoviclz Khanzhonltov carrying out research a visit to the laboratories of the Central Institute of Aero- with a sjculc model of the "Sormovich" in the wind tunnel at dynamics at Leningrad, where the fundamental research work Leningrad Central Institute of Aerodyizamics in connection with these vehicles would appear to be con- ducted, and of a trial run on the River Neva aboard the fifty- seater Sormovich on or about December 6th, 1966, when the Little is written about the actual trial of the Sormoviclz, but river was on the point of freezing-up for the winter. This trial it would appear that it passed oH satisfactorily and that she run is described as "one of the last to be carried out this year", will really be in service, on probation, next summer. What is and one gathers that there has been some kind of hitch with of interest, however, is the correspondent's description of a this prototype fifty-seater, as it is stated that it had been in- documentary film which he claims to be the first man to have tended that she should be on trial in actual operation, presum- seen, apart from the research workers a1 the Institute of Aero- ably on the River Volga, during the past summer, but no dynamics. It would appear from this film that Soviet research details of this have been published. workers, acting on an idea advanced as early as 1927 by Kon- The trial was attended by Vladiniir Borisovich Lyetistkiy, stantin Eduardovich Tsiolkovksiy, better known for his work representing the Krasnoye Sormovo shipyard, at Gor'ki, where on rockets, for an air cushion train (such as is now in develop- the Sormovich was designed and built, Mr Al'bert Abramovich ment in France), actually built and did trials with a hovercraft, Zhivotovskiy, chief constructor of that yard, and Mr Valeriy the two-seater L-I, as far back as 1934. This vehicle is shown Romanovich Shevberg, ~vhodesigned the vessel and supervised in the film running at high speed along a river, doubtless the her building, the pilot and engineer being Messrs Min Alek- Neva, down to the sea, where she beached herself and displayed seyevich Semyonov and Vitaliy Georgiyevich Savinovskiy. her manoeuvrability on dry land by turning round on a very Much of the theoretical work would appear to have been done, small patch of the shore. The film also showed a later model, however, by Mr Valentin Ivanovich Khanzhonkov, Candidate the L-5, considerably larger and evidently much faster than the in Technical Science, shown in a photograph carrying out L-I, travelling over swamps and sand spits, etc. research with a scale model of the Sormovich in the wind tunnel at the Leningrad Central Institute of Aerodynamics, "Sormovich" Specifications where he was interviewed by the correspondent, who described Fifty passengers. him as "the father of contemporary hovercraft", of which he Maximum speed of 64.5 knots. is "keenly enthusiastic". It was on the basis of data derived Hull made of light aluminium alloy consists of separate units from such tests in this wind tunnel that the early Soviet hover- and blocks welded together. craft, the thirty-eight-seater Neva, built in Leningrad, and the Length overall, 26.5 m (101.85 fl). smaller Raduga, built at Gor'ki, as well as the Sormovich, here Beam, 10 m (32.81 ft). in consideration, were designed. Moulded depth of 4m (13.12 ft). An aviation-type Tvchenko AI-24 gas turbine of 1,800shp Rnclugu, the Taiga has been des~gnedspec~fically lor the Soviet is installed in the stern, driving the single lift fan and two logglng Industry She may be used for cleallng jammed logs shrouded propellers. The air cushion developed through the and rafts durlng tllnbel flotage as well as for refloat~ng logs fan by peripheral jets totals 165 sq m (1,775 sqft) and aheight thrown out on to the banks As she wrll be equlpped wlth a 0 of 211.30 cm (7.87-11.81 in), powerlul wlnch, ~t will also be poss~bleto use the Tnlga as a The Sormovicll is steered by two air rudders installed directly tug A passenger verslon for sholt local servlces and an ambu- behlnd the propulsion airscrews and is claimed to be hirzhlv lance verslon are also belng developed In all verslons powel rnanoeuvrabie even at ~peedsof 100 km/hr (about 53 knitsj. will be plovlded by an unspecified gas turblne drlvlng two lift The power unit, rudders and auxrllary system controls are fans developlng a 12111 cush~on The Talgu's overall length 1s operated automatically from the bow wheelhouse. Turbine 42 ft 8 In, her beam 19 ft 8 In and he1 speed 26 knots noise has been controlled by isolating the englne from the Wlth an rnland wate~wayssystem of 300,000 km (187,500 passenger cabin by a soundprool bulkhead. The passenger cabin mlles) wlth depths below 1 m, whlch cannot be negot~ated partitions have been lined with soundprool plastic material. by convent~onal 01 hydroi'o~l elaft, the Sovlet Un~onoffers 9 splendld prospects €01 ACVs and lhe current Flvc-Year Plan provldes for the development and const~uct~onof twenty- to "Taiga" thlrty-seater ACVs with speeds of up to 35-40 km/hr (19-21 5 A general purpose craft for operation on rivers running knots) Icebound Ilvers wlll become navigable the yea1 round Lhrough virgin forests. Developed from an earlier craft, the Tl~alsare proceed~ngw~th expenmental cross-countly ACVs

(Part XIII) by Leslie Hayward

SSR

o country rn the world IS so rich In navrgable rlvers, N lakes and waterways than Russia, therefore ~t 1s not Early versrons of thls double deck, alumrnrum hulled surprlslng that Russran engrneers have applied the~rskrll craft, burlt rn the Sormovo sh~pyardsto the deslgns of and knowledge to the desrgn and product~onof varrous the Alexeyev team uere powered by a 800 hp dresel englne, types of comniercrally operable hydrofoil craft. Serrous drrectly geared to a slngle propller, through a revers~ble and log~caldevelopment In the Sovret Un~oncan be traced clutch. Later verylons are powered by 903 hp or 1,000 hp from the latter part of 1945 when an experlmental desrgn englnes. team, headed by Rostlslav Yevgenrevich Alexeyev based at the Krasnoye Sormovo shrpyards at the rlver port of Length overall ...... Gor'ki, on the Volga rlver, experimented with a small self- Breadth overall ,,, ... propelled raft-type launch fitted wlth varying arrangements Maximum draught : and types of fully submerged fo~ls. Four experlmental Pull displacement role . . . 5ft 11 in (1.8m) craft were burlt and used for ~ntensrvedevelopment trials When on foils ...... 3 ft 7 in (1.1 m) before work was started on the deslgri of a large passcnger Total displacement ...... 24 tons carryrng craft Useful load ...... 6.5 tons In Junc 1957 the Russians launched therr first passenger Maximum speed ...... 40 knots carrylng hydrofo~lvessel, the Raketa (Rocltet), the first Cruising speed ... ,.. 33.5 knots trral servrce being opcrated along the Volga between Passenger capacity ...... 66 persons Gor'kr, Cheholtsary and Kaznn on August 25th, 1957. As @ further craft hecarne avarlable, servlces were ~nauguratcd Wrth the engine developlng 650 hp at 1,200 rpm, the on the Dn~eper,Ob, Yenrser and Lena rlvers. More recently crurslng speed rs 33.5 knots and the fuel consumption is a craft has been operating In Siberra between the lndustr~al approximately 63 gallons or 635 1b for 100 mlles (170 kg centres of Pavlociar and Omsk on the Irtysh rrver. per 100 km) and the range is 466 miles (750 km). Figure 91. "Raketa" Figure 92. Colzstruction of the ufter bracket after modificution to the "Raketa"

Durrng the latter part of 1959 considerable redes~gnwas Considerable numbers of both types of this craft are on carried out on a Raketa craft to adapt it for usc 111 water- regular scheduled services on many of the major Russian ways too shallow for the standard craft to operate. Major rivers. Regular services have also been establrshed on the modifications rncluded moving the propeller further aft Danube between the Bulgarian ports of Rousse and Silistra and posltroning it above the stern forl. Engine bearers and Rousse and Svishchov, and between Belgrade and were glven a new angle necessitating a new rear bearing Brahovo on the Yugoslav - Rurnanran bordcr. The Hun- to accommodate the modrfied angle of rnclination of the garian Navigation Company operate a service between propeller shaft. The overall height of the rudder was Budapest and V~enna. reduced but its length was increased. As the propeller was not completely immersed rts eficiency was somewhat Meteor reduced so the load draught was reduced, 48 passengers The Meteor, another product of the Alexeyev design being carried instead of 66. The fuel load was also team made its first journey to Moscow from the shipyards reduced. at Gor'ki in the summer of 1960. In add~tionto scheduled The first tr~alrun of the shallow-draught Knketn took services over th~sroute many craft are now opcratrng on place in November 1959 and was from Gomel to Kiev inajor rrvers in Russia. and back, a distance of 414 m~les(668 km). The tests were not entirely satisfactory as rt was found that the craft was Length overall ...... difficult to steer at high speed. A high pressure, hydraulrc- Breadth overall ...... Maximum draught : ally operated servo system was ~nstalled to actuate the Full displacement role . . . rudder, the pump berng drrven from the propeller shaft. When on foils ...... This mod~ficatlonmade consrderable improvement in the Overall height above watcr steering of the craft as drd the subsequent addrtlon of a when foilborne ...... 22ft 4 in (6.8 m) Total displacement ...... 53 tons three fin rudder, but the central fin being m the pulsatrng Maximum speed ...... 49.7 knots stream produced by the propeller caused consrderable Cruising speed ...... 33.5 knots vibration to be transmitted back through the hull structure. Passenger capacity ...... 150 persons in the final desrgn two separate rudders were fitted, each with rts own hydraulically operated assrster gear. A bow Passenger accommodation IS varied to su~tthe type of rudder was also fitted to the central support of the front servlce provrded. On suburban services, bench seats take foil. The draught of the finally moclrfied Raketa 1s 3 ft 9 In 150 passengers but on long distance services, Ilghtweight, (1.15 m) and the maximum draught when on folls is 20 In aircraft-type seats take 130 passengers. The luxury of a (0.5 m). Speed of the craft is reported to he 37.3 knots bar, promenade decli, cabin arr-condit~oningand tempera- (60 ltni/hr). ture control is present on both typ-s of craft. 9 Figure 94. "Meteor" Figure 96. "Sputrlik"

Meteor 1s powered by two 900 hp, 12 cylmder, water Sputnik cooled, supelcharged "V"-type d~eselenglnes. Each engine Bullt for operat~onon lriland waterways and large lakes IS arranged to drive rts own propeller shaft and the twln such as the Casp~anSea, Lake Ba~ltal,etc, Sputnik made screws contra-rotate to balance out torque. Apart from ~tsrna~den voyage durrng October 1961 coverlng the drs- small, exposed fore and aft deck areas the hull and super- tance between Gor'k~ and Moscow, approx~mately 560 structure are burlt as an rntegral unrt, the hull belng framed miies, In 14 hours. on long~tudlnaland transverse formers. Steel constructlon n~embersare welded together but the alumrnrum alloy skrn Length ove~all structure 1s riveted rn place. B~eadthoverall Submerged horrzontal folls, havrng convex cross sec- Max~n~umdraught ttonal centre portrotls, are fitted at both the bow and stern Full d~~placementrole When on foils and In addit~ontwo small subfolls project outwardly from Overall helght above water the bow foll s~desupports, a central keel-type support I? when lollbolne also used for the bow folk The stern folk are attached to Total d~splacement 110 tons the hull by s~desupport.; only, the supports being provlded Maxlmum speed 49.7 knots wrth large rnwardly d~rectedflanges so that the lncrdeace Clu~slngspeed 4 1.0 knots Passenger capacrty 260 to 300 or angle of the foil may be changed to su~tvarlous operat- Ing condrt~onsby ln3ertion of wedge plates between the S~~utnzk1s fitted with four 900 hp dlesel engrnes and for1 and the support flanges before they are bolted together has a cru~srngrange of approxrmately 500 mlles An all- On June llth, 1962, Meteor craft establrshed a regular welded hull permrts sectional constructlon to be employed servrce on the Moscow - Volga canal and other services and drspersed fabr~catronof various sect~ons Thrs type of are now operatrng on many lakes, rlvers and waterways unlt constructron enable? standard sectrons to be used on a varrety of d~fferent craft A cons~derableamount of MIR plastlc materral 1s incorporated In the superstructure whlch, In the autumn of 1961, the first Russran bullt sea-gorng In adci~t~onto reduclng the we~ghtof the craft, has also hydroforl sh~pmade rts appearance. MIR a 92 passenger solved some of the corrosion problems. craft, burlt as a prototype of the later Co~nlorcraft, com- The passenger saloons, arranged as three separate corn- pleted successful trrals rn the Black Sea durrng September partnients are insulated against heal and noise and fitted 1961. The hull 1s of welded alumlnlum alloy and the out w~thfire reslstrng materials Accommodatron tor 68 surface plercrng hydroforls are made of h~ghtens~le staln- passengers IS prov~dedIn the fully glazed front saloon and less steel. Thls craft IS sad to have a speed of 46 6 knots. for 96 passengers rn both the central and rear saloons Ry Cosmos umg bench-tvpe seatlng, accommodat~oncan be rncreased L~ttleis ltnown about the Cormor craft except that the to 108 In each of these two saloons. Two cab~nsare pro- englnes are controlled from the wheelhouse and an auto- vrded for the crew. Overcoats, heavy luggage, etc, can be lnatrc servo-operated helmsman has been mstalled to take housed in a specral compartment. A series of rotatable care of emergencres. The forls are sald to be of hrgh cowls, heated by a closed clrcu~thot water system, provlde tensile starnless steel and the craft 1s reported to have a ventrlat~onfor all compartments. Approx~mately85 gallons top speed of 46.6 knots. of drmklng water 1s carried and suct~onpumps provide filtered sea water for other purpose?. A well stocked buffet and store room caters for passengers' needs Safety precautrons have been carefully planned. In add~t~onto a mechanrcally drlven pump capable of movlng 235 cu ft of water per hour, an auxrl~ary hand pump can be used for pumplng out the ellglne room. Flre extlngurshers are fitted In the wheelhouse, passenger saloons and engrne room. Two Inflatable rubber drnghys are carr~ed,and lifebelts are provicled for all passengers and crew. Telephonrc and loudspeaker commun~catlon1s provrded throughout the craft and rad~otelephones provlde Figure 95. "Mir" external communrcation. Sputnlk, nav~gated from a forward wheelhouse, has electro-hydraulrcally controlled cnglnes and rudders. A 24 v electrrcrty supply rs produced from generator? powered by the maln englnes. A d~esel-engrnedauxrllary power unrt produces an emergency supply of electrrc~ty,compressed alr for startrng the rnarn englnes, power for operatrng tile brlge pumps, and many other servrces. Fully submerged forls are supported by marn struts depending from the hull structure. To glve laterlal stabrlrtv, two auxrlrary rolls project outwardly from the front maln support struts. At hrgh speeds the auxrllary foils are nor - mally clear of the water surface. Structural farrlng, pro- Figurc 98. The engine, dashboard, seats arzd steering wheel orz tlze Molrzicr are tlze same as those used for the "Volga" ject~ngfrom the srde of the hull over the support struts, prevent the foils from damage when docklng and also assrst navrgation by vlsually lndlcating the maxrmum width of the craft.

Molnia The lrght alloy hull of the craft 1s separated Into three This six-seater, open cockpit, water-taxi and runabout compartments by framed metal bulkheads. The front com- pleasure craft, capable of speeds up to 42 knots and having partment IS used for general stores, the central compart- a range of approximately 90 miles per hour, was exhibited ment forms the open cockplt w~thseatlng for srx people, at Earls Court in London during July 1961. Built at thc and the rear compartn~enthouses a 77 bhp modified car Ratoum and the Sormovo Shipyards, many hundreds of engrne and gearbox. this type of craft are widely distributed throughout Russia. Lrfe jackets are incorporated rn the seat cushrons and a Lake Baikal in Siberia, now developed as a popular lrfebelt wrth lrfeline 1s carrred. Brooke Marlne Ltd, of summer resort, is often the scene of much Molnla activity. Lowestott, Suffolk, have one of these craft rn therr shrp- yard. A contract has recently been signed between Length overall ...... Sudorrnport and the Amerrcan Satra Corporat~onfor the Breadth overall Maximum draught : delivery of ten of these craft to the Unrted Stater durrng Full displacement role ... (2ft8in(0.85m) 1967. When on Foils ...... I ft 9 in (0.55 m) Total displacement ...... 1.75tons Maximum speed ...... 42 knots Cruising speed ...... 35 knots Passenger capacity ...... 6

LA Figure 97. "Molnia" MERCANTILE MARINE ENGINEERING AND GRAVING DOCKS CO. S.A. ANTWERP Dry Dock Owners Ship Repairers and Engineers

Ofice.5 and Works : Hansadsk 403 - Antwerp Agents for Messrs. J. & E. Hall, London, and Telephone : (03) 41.04.20 Messrs. Thr~ge-T~tan-A/S,Copenhagen Telex : Shaft~ngAn 31219 B Telegrams : Shaft~ngAntwerp Agents for United Kingdoin and Ireland : ANDREW LOW, SON & CO., LTD. All conversions to engines and hull Bevls Marks House - Bev~s Marks - London, E.C.3 Telephone : Avenue 2383 Barges equipped for cleaning oil tanks Teleg. Address : Andolow - London - E.C.3 Gritblasting of ships' shell and bottom plates HENRY T. MEADOWS & SONS Five private dry docks for vessels up to 75,000 1.d.w. 6 Broad Street Place - London, E.C.2 Telephone Office : London Wall 244516 BURMEISTER & WAIN LICENSED REPAIR SHOP Telex : London 264474 (Hooky) AND APPROVED SPARE PARTS SUPPLIERS Teleg. Address : Hooky London E.C.2 0 GREEK SHIPPING - LONDON CAPMARINE AGENCY LTD. REPAIRING FACILITIES AT GHENT 11 Goring Street - London E.C.3 Offlces : Langerbruggestraat Telephone Office : Avenue 565213 Oostakker - Ghent Teleg. Address : Inland : Camar Fen Telephone : (09) 51 13.40 Foreign : Camar